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AS 1 Basic Concepts in Physical and Inorganic Chemistry

8 dot points across 8 inquiry questions. Click any dot point for a focused answer with worked past exam questions where available.

How do chemists count atoms and reacting amounts using the mole?

The mole and the Avogadro constant, molar mass, empirical and molecular formulae, the ideal gas equation, concentrations of solutions, and reacting mass, gas volume and titration calculations including percentage yield and atom economy.
A CCEA A-Level Chemistry answer on the mole and the Avogadro constant, molar mass, empirical and molecular formulae, the ideal gas equation, solution concentrations, and reacting mass, gas volume and titration calculations including percentage yield and atom economy.
9 min answer →

How is the atom structured, and how do mass spectrometry and electron configurations explain its behaviour?

Sub-atomic particles, isotopes and relative masses, the mass spectrometer and relative atomic mass calculations, electron configuration in s, p and d sub-shells, and ionisation energy evidence.
A CCEA A-Level Chemistry answer on sub-atomic particles, isotopes and relative masses, how the mass spectrometer works and is used to find relative atomic mass, electron configuration in s, p and d sub-shells, and the ionisation energy evidence for shells and sub-shells.
9 min answer →

How are atoms held together, and how does the type of bonding explain a material's properties?

Ionic, covalent, dative covalent and metallic bonding, electronegativity and bond polarity, electron-pair repulsion and the shapes of simple molecules and ions, and the link between structure and physical properties.
A CCEA A-Level Chemistry answer on ionic, covalent, dative covalent and metallic bonding, electronegativity and bond polarity, electron-pair repulsion theory and the shapes of simple molecules and ions, and how structure determines physical properties.
9 min answer →

How is energy transferred in reactions, and how is enthalpy change measured and calculated?

Enthalpy changes and standard conditions, exothermic and endothermic reactions, enthalpy of combustion, formation and neutralisation, calorimetry, Hess's law and enthalpy cycles, and mean bond enthalpy calculations.
A CCEA A-Level Chemistry answer on energetics, covering exothermic and endothermic reactions, standard enthalpy changes of combustion, formation and neutralisation, calorimetry and the q = mc(delta T) calculation, Hess's law and enthalpy cycles, and mean bond enthalpy calculations.
9 min answer →

How do reversible reactions reach equilibrium, and how do conditions shift it?

Dynamic equilibrium and reversible reactions, Le Chatelier's principle and the effects of concentration, pressure and temperature, the role of a catalyst, the equilibrium constant Kc, and applications to industrial processes such as the Haber process.
A CCEA A-Level Chemistry answer on chemical equilibrium, covering dynamic equilibrium and reversible reactions, Le Chatelier's principle and the effects of concentration, pressure and temperature, the role of catalysts, the equilibrium constant Kc, and the compromise conditions used in industrial processes such as the Haber process.
9 min answer →

What forces act between molecules, and how do they explain physical properties?

Van der Waals (London) forces, permanent dipole-dipole forces and hydrogen bonding, how they arise from electronegativity and polarity, and how they explain boiling points, solubility and the anomalous behaviour of water.
A CCEA A-Level Chemistry answer on intermolecular forces, covering van der Waals (London) forces, permanent dipole-dipole forces and hydrogen bonding, how polarity and electronegativity create them, and how they explain trends in boiling point, solubility and the anomalous properties of water and ice.
9 min answer →

What controls the rate of a reaction, and how do catalysts and temperature change it?

Collision theory and activation energy, the effects of concentration, pressure, surface area, temperature and catalysts on rate, the Maxwell-Boltzmann distribution, and how a catalyst provides an alternative pathway of lower activation energy.
A CCEA A-Level Chemistry answer on reaction kinetics, covering collision theory and activation energy, the effects of concentration, pressure, surface area, temperature and catalysts on rate, the Maxwell-Boltzmann distribution, and how catalysts lower the activation energy by providing an alternative route.
8 min answer →

How do we track electron transfer using oxidation numbers and half-equations?

Oxidation and reduction in terms of electron transfer, oxidation numbers and the rules for assigning them, identifying oxidising and reducing agents, and constructing and combining half-equations into balanced redox equations.
A CCEA A-Level Chemistry answer on redox chemistry, covering oxidation and reduction as electron transfer, the rules for assigning oxidation numbers, identifying oxidising and reducing agents, and constructing and combining half-equations into balanced overall redox equations.
8 min answer →